Conduit for electric wires.



PATENTED APR. 3, 1906.

D. H.. MURPHY. GDNDUIT FOR ELECTRIC WIRES.

APPLICATION FILED JUNII9.1902.

. of Wisconsin, have lnventednew 5 with a sra'rns era a oration.

DANIEL HAYES MURPHY, OF

SAFETY ARMORI'IE CONDUIT O VANIA, A CORPORATION MILWAUKEE, WISOONE HN, ASSIGNOR TO OMPANY, Oi? Pl'lTTSBUltG, PENNSYb OF PENNSYLVANIA.

No. emcee. j

Specification ofLetters Patent.

Itatented April t'l, 1908.

Application filed June 9, 1902. Serial No. 110,719.

To all whom it may concern: Be it known that I, DANIEL Hares itlcsrny, a citizen of the United States, residing at Mil- Waukee, in the county of Milwaukee and State i and useful Improvements in Conduits for Electric Vtires, of which the following is a specification.

The object of this invention is to increase the utility and cfliciencg of electrogalvanized [O conduit-tubing and to ular fittings, the invention consisting of a steel or iron tube coated externally by a deposit of zinc and inter-- nally by a flexible enamel, as hereinafter more particularly set forth with reference to the accompanying drawings, in which like letters designate the same parts in both figures.

Figure 1 is a side elevation of a partly broken piece of steel or iron tubing having an outer coating of electrodeposited zinc and an inner elastic or flexible coating, and Fig. 2 is a transverse section of the tube.

Referring to the drawings, A indicates a piece of steel or iron tubing having an extenor coating B of zinc deposited by an electroyt c process and an interior exible material.

In carrying out my invention I first clean the'surface of the pipe, preferably by pickcoating 0 of 3,0 ling and sand-blasting in the usual manner.

After the pipe is thus prepared I apply a metallic coating to one surface, either by electrogalvanizing or any other desirable meth- I then coat the other surface of the pi e flexible enamel composition. The metallic coatingis applied to the outside of the pipe, and this enamel com osition in the form of a liquid may be applied to the inte rior by pouring, forcing, or sucking the liquid 4.0 through the pipe The elastic or iiexible composition for the interior coating of the conduit in W be made up as follows: One -allon heavy itch var nish, one pint boiled linseed-oil, pints a5 turpentine. This preparation ilc over the inner surface, allowed to drain a few hours, and then baked at a temperattnie of about 250 Fahrenheit for about three beers and a half Wlll produce a smooth, tough,

5o flexible coating which adheres perfectly to the metal.

Wires through the conduit.

metal. pipe having Aftermanufacturingelectrogalvanized conduit tubing for over a year end er United States Patent No. 645,187, issued March 13, 1900, to Cordtlandt D. Richmondt, I find that in order to make a satisfactory article of this kind suitable for an electric-Wire conduit it is necessary to apply the inner flexible coating "directly upon the bare llOD or steel and not upon a primary coating of zinc. The flexible coating does not adhere Well to zinc, and as it is often necessary to bend these conduits in fitting the coating is likely to be separated from the'wall of the tube. r On the other hand the coating will adhere perfectly to the iron or steel itself, and when applied in this Way there is no danger of its parting from the iron or steel wall when the tube is bent.

The advantages of from the cheap simple method of obtaining a pipe with a metallic coating on one surface and a non-metallic coating on the other surface, Where the metallic coatingis on the outside, it presents advantages in not being liable to craclrin unloading, and s upment and is not liable to be defaced during cutting the ipe to lengths. It also prevents corrosion. n. such case the non-n1etallic coating on the smooth polished surface, which prevents lias bility of stripping the insulation of! the Wires and affords a smooth raceway for fishing the it also acts as an insulator.

The metallic coating may be applied either before or after the applying; oi the nonmetal lie coatinc', and many other variations maybe made in th as in preparing the pipe, 5520., Without eparting from my invention.

I clairn-- 1. as a new article of ihanufacture, a metal pipe having a metallic coating on one surface and a flexible enamel coatingap lied directly to the other surface substantially as described 2. As a new article of manufacture, a a metallic coating on its outer surface and a flexible enamel coating applied directly to its inner surface; substantla 1y as described.

3. its a new article of manufacture, a

my invention result or breaking oii in loading,

c manner of applying the coatin s,

interior gives a metal pipe having an elecirogalvanized me- In testimony whereof I have signed my tallic coating on its outer surface and a flexiname to this specification in the presence of io ble enamel coating applied directly to its intwo subscribing Witnesses.

ner surface; substantially as described. V D HAYES MURPHY 4. A'tube of iron, electroplated on the outside with zinc and havin a flexible inside Vitnessesi coating of enamel applied irectly to the iron 0. C. PERLICK; of the tube, substantially as described. F. W. JONES. 

